A device of this type, which provides a non-permanent attachment between a respiratory mask and a helmet is described in French patent application no. 2,532,552 and European patent application no. 0,105,813. The device in question enables a person utilizing a helmet to place the respiratory mask on the face without having to remove the helmet. This device may have a very simple structure since it is sufficient to provide on the headpiece of the helmet two lateral engagement catches such as parts connected to the headpiece or formed as a unit with the headpiece. Such an assembly would be of interest principally to firemen, the military and the forces maintaining order, for certain activities.
The telescopic structure of the attachment arm and its interior spring permit the application of the respiratory mask onto the face of the person utilizing the helmet with sufficient tightness at the periphery of the mask and without effecting an preliminary adjustment of the length of the arms.
Nevertheless, when during the utilization of the helmet with the respiratory mask, the perspiration of the face produces a slippage of the mask so that it is desirable to compensate this effect by increasing the tension of the attachment arms. More generally, the need exists to make an initial adjustment and above all for subsequent readjustment of the application force of the respiratory mask on the face of the person wearing the mask.